title: Enhanced osteoporotic bone regeneration by strontium-substituted calcium silicate bioactive ceramics.
abstract: The regeneration capacity of the osteoporotic bones is generally lower than that of the normal bones. Current methods of bone defect treatment for osteoporosis are not always satisfactory. Recent studies have shown that the silicate based biomaterials can stimulate osteogenesis and angiogenesis due to the silicon (Si) ions released from the materials, and enhance bone regeneration in vivo. Other studies showed that strontium (Sr) plays a distinct role on inhibiting bone resorption. Based on the hypothesis that the combination of Si and Sr may have synergetic effects on osteoporotic bone regeneration, the porous Sr-substituted calcium silicate (SrCS) ceramic scaffolds combining the functions of Sr and Si elements were developed with the goals to promote osteoporotic bone defect repair. The effects of the ionic extract from SrCS on osteogenic differentiation of bone marrow mesenchymal stem cells derived from ovariectomized rats (rBMSCs-OVX), angiogenic differentiation of human umbilical vein endothelial cells (HUVECs) were investigated. The in vitro results showed that Sr and Si ions released from SrCS enhanced cell viability, alkaline phosphatase (ALP) activity, and mRNA expression levels of osteoblast-related genes of rBMSCs-OVX and expression of vascular endothelial growth factor (VEGF) without addition of extra osteogenic and angiogenic reagents. The activation in extracellular signal-related kinases (ERK) and p38 signaling pathways were observed in rBMSCs-OVX cultured in the extract of SrCS, and these effects could be blocked by ERK inhibitor PD98059, and P38 inhibitor SB203580, respectively. Furthermore, the ionic extract of SrCS stimulated HUVECs proliferation, differentiation and angiogenesis process. The in vivo experiments revealed that SrCS dramatically stimulated bone regeneration and angiogenesis in a critical sized OVX calvarial defect model, and the enhanced bone regeneration might be attributed to the modulation of osteogenic differentiation of endogenous mesenchymal stem cells (MSCs) and the inhibition of osteoclastogenesis, accompanying with the promotion of the angiogenic activity of endothelial cells (ECs).
authors.affiliation: State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050, China.
authors.forename: Kaili
authors.initials: K
authors.lastname: Lin
authors.forename: Lunguo
authors.initials: L
authors.lastname: Xia
authors.forename: Haiyan
authors.initials: H
authors.lastname: Li
authors.forename: Xinquan
authors.initials: X
authors.lastname: Jiang
authors.forename: Haobo
authors.initials: H
authors.lastname: Pan
authors.forename: Yuanjin
authors.initials: Y
authors.lastname: Xu
authors.forename: William W
authors.initials: WW
authors.lastname: Lu
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Zhang
authors.forename: Jiang
authors.initials: J
authors.lastname: Chang
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001861:Bone Regeneration / Q000187:drug effects / Q000502:physiology*; D017610:Calcium Compounds / Q000737:chemistry*; D002460:Cell Line; D002516:Ceramics / Q000737:chemistry*; D016228:Endothelial Growth Factors / Q000235:genetics / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D005260:Female; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D011916:Rats, Inbred F344; D060888:Real-Time Polymerase Chain Reaction; D017640:Silicates / Q000737:chemistry*; D013324:Strontium / Q000737:chemistry*; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
chemical_list: D017610:Calcium Compounds; D016228:Endothelial Growth Factors; D005419:Flavonoids; D007093:Imidazoles; D011725:Pyridines; D017640:Silicates; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580; C031293:calcium silicate; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D013324:Strontium
keywords: Angiogenesis; Bioceramics; ERK/p38 signaling pathways; Osteoclastogenesis; Osteogenesis; Strontium-substituted calcium silicate